Single carrier, sound and color vision pulse system



Jan. 30, 1951 E. LABIN ETAL SINGLE CARRIER, SOUND AND COLOR VISION PULSE SYSTEM Filed Sept. 27, 1945 3 Sheets-Sheet l Eff wm b aw. E@ S 1m Y SWL BX mmvw, m Ema. w www; QN W50 T ||h IINMWINIII NRWQ Il Il lwwf( A N\\|Qw QN SINGLE CARRIER, souND AND coLoR vIsIoN PULSE SYSTEM Filed sept. 27, 1945 Jan. 30, 1951 E. LABIN ErAL 3 sheets-sheet 2 Jan. 30,

E. LABIN ETAL SINGLE CARRIER, SOUND AND COLOR VISION PULSE SYSTEM Filed Sept. 27, 1945 zu wmamrak 5 Sheets-Sheet 3 How/avra surfe/w 45M 34% atented jan. 30,

UNI TED STAT ES VV P?AIENT OFFICE SINGLE CARRIER, SOUND isfncoriit VISION PULSE SYSTEM poration of Delaware Application september 2r,f1945,seriarNt; 618,966

3 claims. (ci. ris- 5.2)

This invention relates to new and useful improvements in televesion transmission systems, but certain features of the invention are applicable also to the transmission of other kinds of intelligence.

An object of the invention is to permit the transmission on a single carrier frequency of signals representing a plurality of different kinds of intelligence, such as picture signals, synchronizing signals and sound signals. Y

Further objects of the invention are the provision of a single signal train of picture signals, synchronizingandsound signalsythe provision of pulses (for .thesynchronizing and sound signals differing inshapecharacteristics from each other.; vand distinguishing certain ofthe signal pulses according vto one characteristic and others by .another characteristic.

.These and other Vobjects Aof the invention will more clearly appear from the followingldescription of a preferred embodiment andthe appended claims. y

V{In the j'drawings Fig lis a curve illustrating the pulses Ytransmitted and received;

Figs. 2, `3 andfl vshow portions of Fig. l on an enlarged scale; Y p

Fig. 5 is a block diagramof as much of a television transmitter as is necessary for understanding-the vvpresent invention Fig. .6 is a block diagram of asmuchof a televlsionlreceiver as is necessary for understanding the-,present invention;

-lg. 7 .shows `one embodiment with circuit which may be used in the receiver of Fig. 6.; and

Fig.` 8is a graph used in explaining the operation ofthe sound channel in the circuit of Fig. 7.

Referring nto Fig. 1, the amplitude modulations ora-carrier representing the picture signals I are separated by horizontal synchronizing puses 2. Each-horizontal pulse is carried by a horizontal blank-ing pedestal 3 on said carrier and carrying in. addition to pulse 2 a second pulse 4 whose spacing with respect to pulse 2 is varied depending` on the sound` to be transmitted. Thus, the tmeor phase modulation of pulse 4 with respect torfpulse-2 is used for transmitting the sound'accompanying the picture signals, and no separate frequency band need be provided for this purpose;

Fig..2 gives anenlarged view of these synchronizing andA sound pulses. Assuming that the width-of the horizontal blanking pulse or pedestal 15.10;.16112. (the distance between the leading and trailing edges), where H is the time consumed Y2 by one horizontal blanking pulse 3 v and Ya line trace signal l, the width of pulse 2-at its top may be-only-onetenth-of lthan-or 016B. Pulse 2 is preferably wider at its base by .00321-1 and it has itslleading .edge substantially .008H from the [leading edge'of .pulse 3 =toinsure-that when'pulse k2 is `super-positioned'on "pulse '3 their leading edges Ywill notbe distorted, as Amight occur when theA timingof these pulses i`s`rnin1ite1y incorrer'zt.` r.the sound pulse is preferably only half as Wide as 2, i. e., .00811, at the top and spreads to the same extent at the bottom as does 2, i. e., it is .0032H wider. -Thefdisplacernent-D ofV the pulse 4 in response to sound modulation may be i0.048H. The guard time intervalle. between the-lagging edge of :pulse A2 and the nearest time displacement limit 4 is .0191-1, and the guardtime interval 12 :just `preceding the lagging edge of pedestal=3and the nearest time displacement limit 4" is .006I-I. It will be understood, of course, that-these relative dimensions are given by 'way of eXarnpleonly.

,--At the end or bottom of each picture frame,

. vertical blanking ytakes place under the control of Va iVerticalwpedestal 8 whose width between lin-es 5--5 `of Fig., 1 may beY equal Yto .0517, where V-is the vertical eld time, that is, the time consumed in transmitting the intelligence for one complete eld. During this-period .05V the sending of horizontal synchronizing pulses and sound pulses -isfcontinued while one or more vertical or frame synchronizing pulses 'l are sent. The leading edge ofjthe rst or only synchronizing pulse-'i L is preferably 1.25H from the leading edge of the last pulse 2X marking the bottom of the picture frame and'coincidingwith line 5. If, as indicated in dotted lines, additional synchronizing pulses such as l', fl", 1"', 1", are placed on pedestal 6, then these are also spaced 1.25H from the next preceding horizontal 'synchronizing pulse For colored television, a color-phasing pulse S is `placed on the Vertical blanking pulse t a sultable period Gc following the-leading edge of `pulse vli. For further details -of color television, lreiercarrier.

Referring to Fig. 3, the width of the vertical u synchronizing pulse 'l is preferably .03151-1 at the top and .0475H at the base or practically twice as wide as a horizontal pulse 2.

Color-phasing pulses 8 are still wider; they may be .l26H wide at the top and .142H at the bottom.

The following tables give by way of example the timing of the various impulses:

WAVEFORM DIMENSIONS IN MICROSECONDS Monochromatic H=22050 cps.=45.4 ,11. sec. Color H=31500=31.7 u sec.

For horizontal blankz'ng pedestal 3 Build-up Decay Sync Sound Guard Guard Mod. Type Pulse Pulse Time Time Displ. 1111512 ggle Width Width A D Sync and Sync M 1 7. 3 0. 7 0. 35 0. 85 OA 3 3:2. 2 0. 07 0. 07 C 1. 5. 0.5 0. 25 0.6 0.2 il. 5 U. 05 0.05

Fm` vertical blanlcing pedestal 6 V Sync V Sync V Sync Color Color Color Blanling Type Pulse Pulse Pulse Pulse Pulse Pulse Repetition Width Buildup Decay Width Buildup Decay Period M 1 1. 5 0. 35 0. 35 lo sec. C l l. 0 0.25 0.25 4.0 0. 25 0. 25 M20 Sec.

1MMonochromatic. C-Color.

Pulse width measured at top of pulse.

Successive frames may be interlaced in any suitable manner.

It is noted again that al1 required picture, sound and color signals are sent on a single carrier and, as will be shown below, require relatively simple and well-known equipment for their generation and transmission.

Fig. is a block diagram of the important elements suitable for the transmission of the signals illustrated in Fig. 1. The horizontal pedestals 3 are generated at I2 and the Vertical pedestals 5 at I3. These two generators are synchronized from signals from source S. Ther pulses generated at I2 and I3 are fed to mixer circuit I4 which transmits them in their time sequence to mixer I5 and to camera I6.

The pulses representing the pedestals 3 are fed through a delay device Il, either electronic or of the passive network type, to a horizontal synchronizing pulse generator I8 which will produce the horizontal marker pulses 2 and feed them to the mixer I5. Similarly, the vertical pedestals 6 are fed by generator I3 through a delay device I9 to a vertical synchronizing pulse generator which will produce the vertical synchronizing pulses l and supply them to the mixer I5. It will be understood, of coluse, that instead of using pedestal pulses 3 and 6 to control generators I8 and 20, signals may be taken from synchronizing source S.

Where color-phasing pulses are required the generator i3 may be connected through delay device 2I to a generator 22 for production of colorphasing pulses S, and these pulses are also fed into the mixer I5.

The generator I8 of the horizontal synchronizing pulses is preferably connected through a delay device 23 with a time pulse modulator 24 for producing sound pulses 4 whose phasing or timing with respect to the marker pulses 2 may be modulated from an audio source 25. The modulator vertical pedestal 6, output of generator I8 is, as

indicated by line 25, inter-synchronized with the also being passed through mixer I5 and then to a further 'mixer 3l to which the camera I5 supplies the picture signals.

The balance of the transmitter may be of any customary type for broadcasting the signals of Fig. 1 or transmitting them through any sultable medium to a receiver.

Only those elements of a receiver are shown in Fig. 6 which are necessary for an understanding of the present invention.

The detector circuit 32 applies the incoming signals after reception by known receiver circuits in parallel to three circuits 33a, 3312 and 33e adapted to discriminate between the pulses according to pulse width, and a fourth circuit 33d to a picture reproducer. Pulse Width discriminator 33a selects only the color phasing signals il,v

pulse width discriminators 33D and 33e select the horizontal and vertical synchronizing pulses respectively.

Circuit 33a responds only to pulses 8 having a width of 5.7 microseconds, removes them by translation and clipper action and sends them to a color utilization circuit 34a. From this point the color control of the receiver may follow any customary pattern.

The circuit 33h removes only the horizontal synchronizing pulses 2 and applies them to a horizontal sweep generator 34h controlling the horizontal sweeping of the cathode ray tube or the like (not shown) of the receiver. v

Circuit 33e segregates the vertical pulses l to operate a vertical sweep generator 34e of the cathode ray tube.

The pulses 4 representing the sound are taken olf at circuit 33o and are sent through differentlator ,network 35 to dernodulator 36 whose. .out put wilhcontain the amplitudamodulated equiva- 'illentof pulses'4. "The soundvlave is fedfvia a '.low passwltersl to vthe sound output. of the-re- 1. ceiver. I

"',The picture Vvsignal responsive, elementsor the receiver may be of any conventional type tdyvhich ,circuit 33d is connected.

"',IWhileL the width discriminators of Fig.l6may 1.be.of. .any.suitable' type, the type-disclosed.,in .the

copendingapplication ofEmile Labin and Donald "D."Grieg,'Serial No.'487,0'2,'led May 15, 1943,

now Pat. No..2,440,278, granted-April 27, 1948, is .preferred. .Theirximportant elements arefshown .#111, Eigfq.

The discriminatori-.33cfFig. 7 consistsqoaiimit clipping tube or amplifier 38, a tuned circuit 39, and an oscillation damping tube 48. ,The amplier tube 38 has its grid so biased that it limits all pulses to a predetermined amplitude for application to the L-C circuit 39 over a resistance R. This circuit is adjusted to be shock-excited to maximum oscillation only by pulses of a predetermined width. The tube 48, bridged across circuit 39, is maintained blocked by the pulse energy applied to circuit 39 over grid connection 40a. The electrode connections of tube 40 are such that the tube conducts only when the oscillations go negative, whereby only a single positive undulation is passed to clipper tube 4I for each input pulse. The input pulse having the width corresponding to the tuning of circuit 39, that is, the one having a width equal to one half the wavelength of the frequency to which the circuit is tuned, will produce the undulations of maximum amplitude. The tube 4l is negatively biased to clip only the maximum undulations thereby rejecting those produced by pulses of width different from the chosen width for the vertical synchronizing pulses.

Similarly, discriminators 33a and 33h are provided with limit clipping tubes 42, 43, L-C circuits 44, 45, and damping tubes 46, 4l, respectively. The -only difference is that the circuits 44, 45 are adjusted for maximum oscillation in response to pulses of widths such as those chosen for the color and horizontal synchronizing pulses, respectively.

The sound pulses 4 are derived from the anode of tube 48 of discriminator 33e, Fig. 7, across resistor 48 and are applied over dilerentiator 35 to the negatively biased control grid 49 of a pentode 5D in demodulator 35. They control the shock-excitation of L-C circuit 5l whose adjustment will determine the translation function of the demodulator.

It should be understood that circuits 33a and 33h may have been provided with a similar resistor 48 for the taking off of pulse energy for demodulator 36, should it be desired. The different types of pulse energy obtained across resistor 48 are indicated by graph A of Fig. 8. When this pulse energy is differentiated at 35 it assumes the shape illustrated in graph B. The pulses 2a, 2b, 4a. and 4b are of much greater amplitude than the derivative pulses la, 1b, 8a and 8b resulting from the input pulses 'I and 8. The reason for this is the dierence in the buildup and decay characteristics of the leading and trailing edges of the input pulses. For example, the pulses 2 and 4 have sharp build-up and decay characteristics while the pulses 1 and 8 have much slower build-up and decay characteristics. Ihus, upon diierentiating the input pulses, the

5 derivative pulseseobtained;:therefrom may be dis'-I crirninated by a proper clippinglevelas indiby the negative biasing of the grid 49 of tube 5! so that pulses 2a andlla, for example, are the only pulses that affect the tuned circuit 5l. The dotted wlines 4b and 4d in Fig. 8cillustrate the .limits 'within which pulses such as l4a may ibe'modulated in time with respect to pulses such :as`2a.

For a'furtherunderstanding of demodulator Y:circuit 36, reference may be had to the copending application, `Serial No. 459,959,f1led September S28, 11942,: nowPat. No. 21,416,306 granted Feb.` 125, i1947. The l demodula-tor operation eiects y a rtrans'lation of the time displacementr of the 4pulses.4ct-'ir1vto-pulses of corresponding amplitude.

This is effected by an interaction between the oscillatory energy from circuit 5I and the pulse energy 2a and 4a. which occurs above the cut-off level of tube 58. The envelope energy dened by the peaks of the output pulses of tube 50 is obtained by low-pass filter 31.

While the invention has been described in connection with a particular embodiment and given pulse dimensions, it will be understood that same is intended to be illustrative of the invention only and not as limiting the scope of the invention as set forth in the objects and the appended claims.

We claim:

1. In television transmission the method of producing a composite television signal which comprises generating regularly repeating vertical synchronizing pulses and color-phasing synchronizing pulses differing in width from each other, generating horizontal synchronizing pulses and sound pulses having further diierence in width and additionally characterized by differences in pulse build-up time from the pulse build-up time of the other pulses, mixing all of said pulses in spaced time sequence to form one pulse train, and transmitting said pulse train.

2. In a television transmission system wherein is produced a composite television signal including pulses utilized for diierent purposes, means for producing vertical synchronizing pulses, horizontal synchronizing pulses, color-phasing pulses, and sound pulses, said pulses differing from each other in width and said horizontal synchronizing and sound pulses having a buildup time dierent from other pulses, means for combining all of said pulses in spaced time sequence to form a single pulse train, and means for transmitting the pulse train.

8. In television transmission the method of producing a composite television signal which comprises generating regularly repeating vertical synchronizing pulses, horizontal synchronizing pulses, color-phasing synchronizing pulses, and sound pulses, said pulses differing from each other in the width thereof, producing a difference in the build-up time of said sound pulses and the horizontal synchronizing pulses with respect to the build-up time of another of said pulses, combining said pulses in spaced time sequence to form one pulse train and transmitting said combined pulse train.

EMILE LABIN. DONALD D. GRIEG. NORMAN H. YOUNG, JR.

(References on following page) 8 RNCES crfEn Number Name Date The following references are of record in the 55' gg me of thls patent: 2:3792146 Beers June 19, 1945 UNITED STATES PATENTS 5 2,461,384 Young June 4, 1946 N b N D t 2,495,252 Goldsmith Aug. 6, 1946 um er ame a e 2,408,063 Grieg sept. 24, 1946 1,678,163 Peterson July 24, 1928 21.414 265 Lawson M Jam 14 1947 1769920 Gray -f. July 8 1930 2;43'7,30o Labin Mar, 9, 1948 2,137,798 Bowman-Man1f01d Nov. 22, 1938 2 465 371 G y M r 29 1949 2 166 688 Ken .nu 18 1939 1 f neg a f y 1 2,486,498 scmesinger Nov. 1, 1949 2,214,846 WllSOn Sept. 17,` 1940 2,268,001 von Felgel-Farnholz Dec. 30, 1941 OTHER REFERENCES 2,295,023 Beatty Sept- 3 1942 Synchronization in Television, pages 8 and 9 2319789 Chambers May 251 1943 y, and Figure 6, Proceedings, Panel No. 8, National 2,326,515 Bartelmk Aug- 101 1943 Television System Committee. 2,333,969 Alexanderson Nov. 9, 1943 

